The present invention relates to disc drive data storage systems. In particular, the present invention relates to a retractable grounding device for spindle motors employed in disc drives and spin-stand testers.
Disc drives are typically used in computer systems as mass storage devices to store recorded data. These disc drives and their test apparatus (spin-stands) usually incorporate one or more discs mounted for rotation on the rotor shaft of a spindle motor. Data is recorded to and read from a plurality of concentric tracks on the discs by an array of read/write heads. The heads are typically moved radially from track to track on the discs by an actuator assembly.
Advances in disc drive technology have revolved around reducing the size of disc drive components and the size of the overall disc drive. Smaller disc drives can allow for a reduction in overall size of computer systems into which disc drives are installed. With the reduction in the size of the disc drive, more space is available within the computer system for other components. In addition to the small disc drives, the disc drive industry has also made advances toward increasing the storage capacity of individual disc drive units.
The reduction in size of the disc drive can compound certain problems often associated with various operational features of disc drives. It also places greater performance demands on spin-stands used to test various components of the disc drive. One such problem involves vibrations or harmonic oscillations in the disc drive and spin-stand tester. The effect of vibrations and oscillations has become magnified as the size of the drive is reduced and data tracks are spaced closer together. As a result, the overall performance of the drive and spin-stand are negatively impacted.
One source of vibration in a disc drive and a spin-stand is the grounding technique used in a typical spindle motor that they employ. The rotor of this spindle motor is electrically grounded through a conductive mechanical connector. One end on the connector is electrically connected to ground and the other end presses against the shaft on the rotor. Rubbing between the mechanical connector and the rotor introduces mechanical vibration into the rotor that gets transferred to the media mounted on the rotor. Media vibrations degrade disc drive and spin-stand tester performance such that reading and writing performance is reduced in a disc drive and read/write head yields are reduced in a spin-stand tester. As explained above, this problem worsens as areal densities (amount of data that can be squeezed on to a given area of the disc medium) increase.
The present invention addresses these problems, and offers other advantages over the prior art.
The present invention relates to data storage systems that include a spindle motor that employs a retractable grounding device that is retracted form a rotor shaft of the spindle motor when the rotor shaft is spinning, thereby addressing the above-identified problems.
A retractable grounding device for a spindle motor having a rotor shaft is provided. The retractable grounding device includes a grounding connector configured to connect the rotor shaft to ground and a position adjuster coupled to the grounding connector. The position adjuster moves the grounding connector between a first position where the grounding connector is in contact with the rotor shaft and a second position where the grounding connector is retracted from the rotor shaft. In addition, a method of selectively grounding a rotor shaft of a spindle motor is provided.
These and various other features as well as advantages which characterize the present invention will be apparent upon reading of the following detailed description and review of the associated drawings.